Repair of the "red green flashing" battery packs.
Repair of the fusible link and chip reset

Sunday, 31 March 2013

Fusible Link Repair

18v LXT
Battery Repair – Chip Reset

By Ryan
Flint – April 2013

Introduction

The Makita range of battery power tools are
undoubtedly the best tools on the market, with the range and availability unparalleled
by any other brand. Unfortunately in the
18v LXT range for the general user the batteries have a tendency to fail and become
useless. As an Electrician/Engineer I thought
there would be plenty of solutions to this problem…..

I have searched the internet in hope that I
could find a solution to my faulty batteries, I have contacted Makita agents and
supposed repair centres all giving me the same advice. Throwing them away and buy new ones...

I decided to ignore their advice and to
have a play around with them and think I have a solution to some of the
problems. Please note that this solution
is not for all problems and that this will void all warranty. If your battery is less than 12 months old and
you have a proof of purchase I advise you to go through the proper channels and
have your battery replaced by Makita.

The common red/green flashing fault on the 18v Makita Charger

Some basic electronic skills and tools such
as a soldering iron, multi-meter and basic hand tools are required for this
procedure.

Opening the
battery

To open the battery you will require a
small flat head screw driver and a T10 long torx bit. Firstly you will notice a white tamper proof
bung in one of the screw holes. Flick
this out with a screw driver and toss it, this will no longer be required. The 4 screws are all that hold the top of the
battery in place. Remove the top and the
white clip (Be careful of the spring under the clip, it could cause a possible
short). You now should see a similar
view to Figure 1.

Figure 1

Testing the
Cells

To test the voltage of each cell use a
multi meter and test the voltage between the 6 points shown in Figure 2. Each cell when fully charged should have
close to 4 volts in it (point 1 to 2) but in most cases we will see much
less. Check between points to make sure
none of the cells have gone to zero. If
one of the cells has gone to zero, the cell will need to be replaced before any
further repair can be done. You may have
several batteries with a faulty cell and my advice is to create a battery from
the spares. (Example: make 3 from 4)

Figure 2

Removing the
Circuit Board

To remove the board several joints need to
be un-soldered and parts removed. Listed
below are the items that need attention.

1.Positive Terminal - unsolder from the board

2.Negative Terminal – unsolder from the board

3.Temp Sensor – glued in (need to lever out, be careful not to damage)

4.Ribbon Cable – remove

5.Screw – removed

Once these parts have been attended to the
board should be able to be removed from the battery pack. The temperature sensor (point 3 in Figure 3) is
glued into place and becomes the hardest part to remove, be careful not to snap
the probe from the board. The ribbon
cable (point 4) is very delicate and also needs careful attention. At all times be careful not to short any
parts of the board or cell pack while removing the board.

Figure 3

Repairing
the Fusible Link

The fusible link being blown has been the cause
of the problem on three of my batteries to date. I have not been able to find any circuit
diagrams online to actually understand what the fuse supplies but I assume it
is the supply to the chip itself.

The fusible link has a black cap (noted F03
on my board) that can be flicked off with a screwdriver showing the metal parts. A solder blob was the applied to the top of
the chip to bridge out the blown section.
This should have hopefully of fixed the problem.

By bypassing the fuse (shown in Figure 6) we
have supplied the chip with power again and in my case it solved the
problem. However as you are bypassing a
fuse the next time such fault occurs there will probably be irreversible damage
to the electronics, so far all is running well in the repaired battery!

Figure 4 - Underneath the board

Figure 5 - Cap flicked off

Figure 6 - Soldered repair of the fuse

Re-Installing
the board

The board can now be reinstalled into the
cell pack and the pack put back together and placed into a charger. A handy hint on reinstalling the circuit
board is installing the ribbon cable first as it is quite difficult once
soldered and screwed back in. Hopefully
your battery pack comes back up to full voltage and runs for many more cycles
giving the Makita tools the customer satisfaction they deserve!

On older battery the MCU used is a FreeScale MC908JK3E witch is based on the Motorola 68HC908Tips : people playing with cars ECU have a need to "unlock" the said chip. Search for UPA-USB Programmer, its looks like their programmer can defeat the security bit present in the MCU allowing us to dump the firmware.On Newer battery the freescale was replaced by a NEC 78k0 (F0513S).On the same path as before some people playing with car IMMO module need to unlock differents flavor of 78k0 chips. Hints : search for NEC Dash Programmer.It worth a try...If i has more time on my hands i would try to power glitch the 78k0 as it seems from some research paper that those chip would be good candidate. NEC has a 10bytes password and FreeScale has a 8bytes one so bruteforcing the whole nspace isnt an option.Power analysis on good response VS bad response while trying the password might reduce the space to search.

I bought a couple replacement boards through alibaba. There's a slight mechanical mismatch to installing in place of the original (newer NEC version) board, but cutting one plastic alignment pin allows it to fit. It has an F9222 chip. They're definitely not identical. After installation in place of the old, I confirmed that it will not talk to the charger as supplied. The charger becomes unresponsive once the battery is installed. I've written the supplier for assistance. I presume this is the board that they use in the half price ($50) replacements also available through alibaba or ebay.

If the supplier can supply all the components it mean either they got their hand on the firmware (illegally dumping it) OR they wrote a new firmware to simulate the Makita's one and is probably not very safe to use unless they wrote a complete BMS system. If they can supply all the parts let me know i would order some board to play with...

I haven't heard back from the supplier yet, but I've attached front and back pictures of the original board (in white on left) and replacement board (in green on right) for your review. See here: http://postimg.org/gallery/8etbc01m/74f7417c/ I have a spare replacement board for $12 if you'd like it.

Thanks, judging by the pictures i was wrong. They replaced the F0513S by a F2222T both are 8bits MCU made by Renesas. The clone one is a 78K0S/KA1+ exactly a NEC (now Renesas) μPD78F9222. So they either dumped the original firmware and adapted it to their board (its not exactly the same circuit) or they wrote their own BMS firmware. One good news tough is the clone MCU can easily be dumped ie : read but im not sure how useful this could be. Yes, i would like to buy your spare :) you can reach me at skaos0110(at)gmail.com. I will give you my address to calculate shipping

Thats great Tutorial for Makita. Some Month ago i had the same idea for Change the Nicd Batterys to LiPo Akkus in a BOSCH cordless drill. If you are interested you found my Tutorial under the URL: http://home.arcor.de/thomas.steffens/html/BOSCH_PSR_Li-Ion.htm

I found the specs for the fuse, it's called a Self Control (SC) Protector: http://www.google.se/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCsQFjAB&url=http%3A%2F%2Ftomsyty.pl%2Fdatasheets%2Fs%2Fsc_protector.pdf&ei=nGR_VOCMOev7ywPLy4GoCw&usg=AFQjCNH_0xQXBNAfcd4BkKsZtvva2aJy6Q&sig2=NLHxutXMVz7ZX6e4t36PvwShouldn't be so hard to find a supplier.

Excellent article! I have seen a lot of different home generator services, but this is excellent! For the very first time i am going to know that a hybrid vehicle can be used as a generator,thanks i am greatly impressed by the work you done! Prius Hybrid Battery

Just replaced the bad cells in my battery from a doner Makita battery. Got the red green flashing. On my circuit board, the fuse was not blown. Tried disconnecting all power from the board for a while, then reinstalling. Same issue. Ordered a new circuit board and will let you all know how it turns out. What a shame because the repaired battery powers my tools fine.

Just one thing about aftermarket batteries PCB : It seems there is no BMS anymore. I mean the new pcb does not monitor each cell voltage (soft ribbon connected to each pair of cells is not present anymore). That could be dangerous if someone uses a new board with a very unbalanced pack.

They should have emulated fixed independant cells value in the firmware. Good to never have any problem with makita chargers but you loose most protections doing that : same as buying aftermarket batteries or charger.

* Want to know how to save money and NEVER buy a new battery again?* How to bring any dead battery back to life again?* Learn how to make $1,000s by purchasing dead batteries and selling them as reconditioned ones for gigantic profits?

This is really an important blog with many helpful information. I have been searching for a long time for this types of content. Keep up posting more and thanks for your great staff.Battery Operated Ultrasonic Level Sensor

my 18V Makita PCM PCB Lithium ion Battery Protect Circuit Module is exzactly the same as yours but online they only sell the ones with the straight battery 'claws' i ordered one hoping it will fit but after opening the battery my broken module is double the size and than yours and my new received one but has not got the curled Battery claws, which i do have in the broken one and you have i see in the picture aswell.Please tel me where i can purchase ont like yours or the dubbel the size one.email me please asap on e.oosterlee@yahoo.com

About rebuilding the Makita BL1830 or others Makita LXT battery packsI'm sure that the issue doesn't come from the main chip that blocked battery packs from been charged anymore!As far as I know nobody ever tried to replace the fuse instead of welding it!Inside the fuse it has a dual Zener diodes, and I'm pretty sure it's checked out by the main chip, that's why after welding it for repairing it the charger is not able anymore to charge the battery pack, what it should be a zener diode with one direction flow it's now shorted.